1. A radar unit is used to measure speeds of cars on a motorway. The speeds are normally distributed with a mean of 90 km/hr and a standard deviation of 10 km/hr.

The fastest 5% of drivers may be considered to be driving recklessly. At what speed would a car be considered reckless?

2. A radar unit is used to measure speeds of cars on a motorway. The speeds are normally distributed with a mean of 90 km/hr and a standard deviation of 10 km/hr.The slowest 5% of drivers are considered to inhibit traffic flow.At what speed would a car be inhibiting traffic flow?

3.A radar unit is used to measure speeds of cars on a motorway. The speeds are normally distributed with a mean of 90 km/hr and a standard deviation of 10 km/hr.

The middle 50% of cars are driving between which two speeds?